WIP PS/2 keyboard driver

pat80-computer/software/z80-assembly/os/drivers/ps2_keyboard.asm

@@ -20,32 +20,53 @@
 ; behave strangely (will drop next pressed key). This is not a problem, as the computer, once completed, will
 ; have a 60% keyboard, without any of the unusable keys.
 
-include "ps2_keyboard_scancodeset2.asm"    ; PS/2 Scan Codeset 2 mappings
+include 'ps2_keyboard_scancodeset2.asm'    ; PS/2 Scan Codeset 2 mappings
 
 ; config (IO port 1)
-PS2KEYB_CLEAR_REG: EQU IO_1
+PS2KEYB_CLEAR_REG: EQU IO_2
-PS2KEYB_DATA_REG: EQU IO_1 + 1
+PS2KEYB_DATA_REG: EQU IO_2 + 1
+
+PS2KEYB_TRANSMISSION_DURATION: EQU 86 ;@ 100khz    ; The time needed for the keyboard to transmit all the 11 bits of data, in CPU clock cycles
 
 PS2KEYB_BREAK: EQU 0xF0 - %10000000    ; The MSB is dropped: see NOTE on intro above
 
-; Reads a single character. 0s are ignored (can be used with keyboard).
+; Reads a single character and returns an ascii code when a valid key is pressed. Blocking.
-; Doesn't check DATA_AVAILABLE register of parallel port, because a 0 byte
-; is ignored anyway (it represents the ASCII NUL control char).
 ; @return A The read character
 PS2Keyb_readc:
     in a, (PS2KEYB_DATA_REG)    ; reads a character
     add a, 0
     jp z, Term_readc     ; if char is 0 (NULL), user didn't press any key: wait for character
-	; check if code is a Break Code (0xF0). If it is, discard next key as it is a released key
+	; we found something, allow the keyboard to complete data transmission
-	ld b, a    ; save a
+	ld a, PS2KEYB_TRANSMISSION_DURATION/5    ; every cycle is 5 CPU cycles
-	cp 0xF0    ; compare a with Break Code
+	ps2keyb_readc_waitloop:
-	jp z, ps2keyb_readc_discard
+		sub 1
+		jr nz, ps2keyb_readc_waitloop
+	; data transmission should now be complete.
+	; check if code is a Break Code. If it is, discard next key as it is a released key
+	ld c, a    ; save a
+	cp PS2KEYB_BREAK    ; compare a with Break Code
+	jp z, ps2keyb_readc_discard    ; if it is a Break Code, jump to discarder routine
 	; we read a valid character: clean key registers
 	in a, PS2KEYB_CLEAR_REG
-	; TODO: Interpretare keycode con lo scan code set
+	; now we will convert keycode in c to ASCII code
-	;ld a, b    ; restore a
+	ld hl, PS2KEYB_SCANCODESET_ASCII_MAP    ; load start of codeset to ascii map
+	ld b, 0    ; reset b, as we are going to do a sum with bc (where c contains the read scancode)
+	add hl, bc    ; add scancode value to map start addr (we are using it as offset)
+	ld a, (hl)    ; load the corresponding ascii code in a for return
     ret ; returns in the a register
 	ps2keyb_readc_discard:
-		; waits for next non-0 keycode and discards it
+		; clean key registers
-		; TODO
+		in a, PS2KEYB_CLEAR_REG
+		ps2keyb_readc_discard_waitfordata:
+			; wait for next non-0 keycode and discards it (it is the code of the released key)
+			in a, (PS2KEYB_DATA_REG)    ; reads a character
+			add a, 0
+			jp z, ps2keyb_readc_discard_waitfordata     ; if char is 0 (NULL), wait
+			; we found something, allow the keyboard to complete data transmission
+			ld a, PS2KEYB_TRANSMISSION_DURATION/5    ; every cycle is 5 CPU cycles
+			ps2keyb_readc_discard_waitloop:
+				sub 1
+				jr nz, ps2keyb_readc_discard_waitloop
+			; data transmission should now be complete, throw away key code
+			in a, PS2KEYB_CLEAR_REG
 	jp PS2Keyb_readc    ; go back and wait for another keycode

pat80-computer/software/z80-assembly/os/drivers/ps2_keyboard_scancodeset2.asm

@@ -0,0 +1,137 @@
+; PS/2 Keycode Mode 2 to ASCII mapping table
+;
+; Keycodes 0 to 83
+
+.db PS2KEYB_SCANCODESET_ASCII_MAP: .db 0	; (Unused)
+.db 0	; F9
+.db 0	; (Control key)
+.db 0	; F5
+.db 0	; F3
+.db 0	; F1
+.db 0	; F2
+.db 0	; F12
+.db 0	; (Control key)
+.db 0	; F10
+.db 0	; F8
+.db 0	; F6
+.db 0	; F4
+.db 9	; TAB
+.db 96	; `
+.db 0	; (Unused)
+.db 0	; (Unused)
+.db 0	; L ALT
+.db 0	; L SHFT
+.db 0	; (Control key)
+.db 0	; L CTRL
+.db 1	; Q
+.db 2	; 1
+.db 0	; (Unused)
+.db 0	; (Unused)
+.db 0	; (Unused)
+.db 3	; Z
+.db 4	; S
+.db 65	; A
+.db 66	; W
+.db 67	; 2
+.db 0	; (Unused)
+.db 0	; (Unused)
+.db 68	; C
+.db 69	; X
+.db 70	; D
+.db 71	; E
+.db 72	; 4
+.db 73	; 3
+.db 0	; (Unused)
+.db 0	; (Unused)
+.db 32	; SPACE
+.db 33	; V
+.db 34	; F
+.db 35	; T
+.db 36	; R
+.db 37	; 5
+.db 0	; (Unused)
+.db 0	; (Unused)
+.db 38	; N
+.db 39	; B
+.db 40	; H
+.db 41	; G
+.db 42	; Y
+.db 43	; 6
+.db 0	; (Unused)
+.db 0	; (Unused)
+.db 0	; (Unused)
+.db 44	; M
+.db 45	; J
+.db 46	; U
+.db 47	; 7
+.db 48	; 8
+.db 0	; (Unused)
+.db 0	; (Unused)
+.db 44	; ,
+.db 45	; K
+.db 46	; I
+.db 47	; O
+.db 48	; 0
+.db 49	; 9
+.db 0	; (Unused)
+.db 0	; (Unused)
+.db 46	; .
+.db 47	; /
+.db 48	; L
+.db 59	; ;
+.db 60	; P
+.db 45	; -
+.db 0	; (Unused)
+.db 0	; (Unused)
+.db 0	; (Unused)
+.db 39	; '
+.db 0	; (Unused)
+.db 91	; [
+.db 61	; =
+.db 0	; (Unused)
+.db 0	; (Unused)
+.db 0	; CAPS
+.db 0	; R SHFT
+.db 10	; ENTER
+.db 93	; ]
+.db 0	; (Unused)
+.db 92	; \
+.db 0	; (Unused)
+.db 0	; (Unused)
+.db 0	; (Unused)
+.db 0	; (Unused)
+.db 0	; (Unused)
+.db 0	; (Unused)
+.db 0	; (Unused)
+.db 0	; (Unused)
+.db 8	; BKSP
+.db 0	; (Unused)
+.db 0	; (Unused)
+.db 9	; KP 1
+.db 0	; (Unused)
+.db 10	; KP 4 -- NOTE: shadowed by break code (see the NOTE in ps2_keyboard.asm)
+.db 11	; KP 7
+.db 0	; (Unused)
+.db 0	; (Unused)
+.db 0	; (Unused)
+.db 48	; KP 0
+.db 46	; KP .
+.db 47	; KP 2
+.db 48	; KP 5
+.db 49	; KP 6
+.db 50	; KP 8
+.db 27	; ESC
+.db 0	; NUM
+.db 0	; F11
+.db 43	; KP +
+.db 44	; KP 3
+; The following codes are unrecognized by PAT80, as it uses only 7 bits (see the NOTE in ps2_keyboard.asm)
+; .db 45	; KP -
+; .db 42	; KP *
+; .db 43	; KP 9
+; .db 0	; SCROLL
+; .db 0	; (Control key)
+; .db 0	; (Control key)
+; .db 0	; (Control key)
+; .db 0	; (Control key)
+; .db 0	; F7

pat80-computer/software/z80-assembly/os/main.asm

@@ -10,9 +10,9 @@ jp Sysinit     ; Startup vector: DO NOT MOVE! Must be the first instruction
 ;       DRIVERS VAR SPACE: 0x9000 - 0x9FFF (4kb)
 ;       APPLICATION VAR SPACE: 0xA000 - 0xFFFF (24kb)
 ; I/O MAP
-;   I/O 0 (0x00 - 0x1F) Parallel terminal (uses addr 0x00 only)
+;   I/O 0 (0x00 - 0x1F) Parallel terminal (uses addr 0x00 and 0x01)
 ;   I/O 1 (0x20 - 0x3F) Sound card (uses addr 0x20 only)
-;   I/O 2 (0x40 - 0x5F)
+;   I/O 2 (0x40 - 0x5F) PS2 Keyboard (uses 0x40 and 0x41)
 ;   I/O 3 (0x60 - 0x7F)
 ;   I/O 4 (0x80 - 0x9F)
 ;   I/O 5 (0xA0 - 0xBF)
@@ -56,7 +56,8 @@ Sys_Printc:
 ; Reads a single character
 ; @return A The read character
 Sys_Readc:
-    jp Term_readc
+    ;jp Term_readc
+    jp PS2Keyb_readc
 
 ; Reads a line
 ; @return BC The pointer to a null-terminated read string
@@ -91,6 +92,7 @@ IO_7: EQU 0xE0
 
 ;include 'drivers/hd44780.asm'
 ;include 'drivers/keyboard.asm'
+include 'drivers/ps2_keyboard.asm'
 include 'drivers/arduino_terminal.asm'
 include 'drivers/sn76489.asm'
 include 'monitor.asm'

prototiping-with-arduino/pal_adapter/pal_adapter.ino

@@ -1,67 +0,0 @@
-#include <TVout.h>
-#include <TVoutfonts/fontALL.h>
-TVout TV;
-
-// Pins
-#define RS 5
-#define EN 4
-const byte DATA [] = {A5, A4, A3, A2, 13, 12, 11, 10};
-
-
-bool clkState = false;
-
-void setup() {
-  Serial.begin(57600);
-  Serial.println("PAL debugger");
-  
-  // Init comm pins
-  pinMode(EN, INPUT);
-  pinMode(RS, INPUT);
-  for(int pin = 0; pin < 8; pin++) {
-    pinMode(DATA[pin], INPUT);
-  }
-
-  // Init VGA
-  TV.begin(PAL,120,96);
-  TV.select_font(font4x6);
-
-  TV.println("TV init");
-}
-
-void loop() {
-  bool newClkState = digitalRead(EN);
-  if (newClkState == false && clkState == true) {
-    // Falling edge: read data from bus
-    onClk();
-  }
-  clkState = newClkState;
-}
-
-void onClk() {
-  bool isCommand = digitalRead(RS);
-  if (isCommand) {
-    //onCommandReceived();
-    onDataReceived();
-  } else {
-    onDataReceived();
-  }
-}
-
-void onCommandReceived() {
-  
-}
-
-void onDataReceived() {
-  char ch = readByte();
-  TV.print(ch);
-  Serial.println(ch);
-}
-
-byte readByte() {
-  unsigned int data = 0;
-  for(int pin=0; pin < 8; pin++) {
-    byte b = digitalRead(DATA[pin]) ? 1 : 0;
-    data = (data << 1) + b;   // Shifta di 1 e aggiunge il bit corrente. Serve per ricostruire il numero da binario
-  }
-  return data;
-}